Second-law analysis of vapor condensation of FC-22 in film flows within horizontal tubes

This study performed second-law analysis on saturated FC - 22 vapor flowing through and condensed in horizontal cooling tubes. An optimum Reynolds num ber existed over the parametric range investigated for the single tube case at which the entropy generated at a minimum rate. For the multi-tube cases , on the other hand, no optimal Reynolds number was identified subject to c onstant surface-area constraint. Furthermore, there was an optimal cooling temperature that: generated a minimum of entropy for a given duty. The pres ent phase-change system was inherently different in thermodynamic performan ce from the single-phase convective system intensively discussed in literat ure works.